This readable document features the history of the first controlled fission reaction at the University of Chicago in 1942. The first section of the document contains an essay based on interviews with more than a dozen of the scientists present at the successful chain reaction on December 2, 1942, as well as the recorded experimental data. The last two sections containing the reminscences of Enrico and Laura Fermi provide insights into the human and technical challenges of constructing and operating the first nuclear reactor also known as a plle.